Known gas turbine engines generally include rows of circumferentially spaced nozzles and buckets. A turbine bucket includes an airfoil having a pressure side and a suction side and extending radially upward from a platform. A hollow shank portion may extend radially downward from the platform and may include a dovetail and the like so as to secure the turbine bucket to a turbine wheel. The platform generally defines an inner boundary for the hot combustion gases flowing through the hot gas path. As such, the platform may be an area of high stress concentrations due to the hot combustion gases and the mechanical loading thereon. In order to relieve a portion of the thermally induced stresses, a turbine bucket may include some type of platform cooling scheme or other arrangements so as to reduce the temperature differential between the top and the bottom of the platform.
Various types of platform cooling schemes are known. For example, impingement cooling is well-known in, for example, stage one nozzle cooling schemes. Due to the fact that most of the pressure drop across an impingement cooling circuit is taken across an impingement plate, however, either the impingement holes generally must be relatively small or the cooling circuit may require more flow to manage the pressure than may be required by the overall cooling requirements. Other types of platform cooling examples include the use of pedestal cooling. Pedestal cooling is known in, for example, stage one bucket trailing edges and the like. Other types of hot gas path components also may require similar types of cooling.
There is therefore a desire for an improved hot gas path component such as a turbine bucket and the like for use with a gas turbine engine. Preferably such a turbine bucket may provide cooling to the platform and other components thereof without excessive cooling medium losses for efficient operation and an extended component lifetime.